Decline in serum progastrin-releasing peptide predicts the response of patients with small cell lung cancer to chemotherapy.

The utility of serum progastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE) as biomarkers for treatment monitoring and as prognostic factors was investigated in small cell lung cancer (SCLC) patients. Patients were first diagnosed pathologically at the First Affiliated Hospital of the University of Science and Technology of China and had their serum ProGRP and NSE levels measured using an electrochemiluminescence immunoassay. A total of 120 SCLC patients were enrolled. In responsive patients, ProGRP levels decreased significantly following two cycles of chemotherapy and continued to decline over the course of treatment. However, this decrease in ProGRP levels was not observed in non-responsive patients. Changes in ProGRP levels were more accurate than changes in NSE levels for monitoring the effects of chemotherapy in patients with SCLC. Following two treatment cycles or after the occurrence of drug resistance, changes in ProGRP levels in patients with low ProGRP levels at the time of diagnosis were not notably, regardless of whether or not patients were responders. The area under the receiver operating characteristic curve of the decline in ProGRP levels as a therapeutic biomarker of SCLC was 0.9643, and the cut-off value was 55.02%. A decline in ProGRP levels maybe a good predictor of objective response to chemotherapy in patients with SCLC with higher ProGRP levels at diagnosis. This model is expected to replace or be combined with imaging to predict chemotherapeutic treatment effects in patients with SCLC.